This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. Primary support for the subproject and the subproject's principal investigator may have been provided by other sources, including other NIH sources. The Total Cost listed for the subproject likely represents the estimated amount of Center infrastructure utilized by the subproject, not direct funding provided by the NCRR grant to the subproject or subproject staff. Asthma is an inflammatory airway disease with characteristics similar to chronic obstructive airway diseases (COPD). In addition to the acute inflammatory response, long-term airway remodeling is typical in asthmatics. Recent work suggests that these permanent changes irreversibly affect lung function. Presently, diagnosis of asthma is based on clinical symptoms. Tests of global pulmonary function such as spirometry may assist in diagnosis. However, diagnosis and monitoring based on clinical symptoms and lung function testing has obvious limitations. Moreover, clinical diagnosis is [unreadable] by definition [unreadable]impossible until the patient already exhibits significant symptoms of disease. This project aims to show that quantitative regional pulmonary markers are highly sensitive to both the acute inflammatory responses and permanent airway remodeling that characterize asthma. Moreover, in light of recent evidence suggesting that airway changes precede the clinical syndrome, quantitative regional markers of lung function and structure can allow for accurate diagnosis before noticeable impairment of respiratory function thereby aiding proper adjustment of therapy. This project aims at using several quantitative hyperpolarized (HP) gas MRI techniques developed to measure regional aspects of both lung structure and function [unreadable]including of apparent diffusion coefficient of helium (ADC, as a measure of lung microstructure), alveolar partial pressure of oxygen (PAO2, as a measure of alveolar lung oxygenation or perfusion), and regional pulmonary ventilation (VA) [unreadable]to assess the sensitivity to acute and chronic disease stages.